feat(client): add url property Response

This will always be the last URL that was used by the Request, which is
useful for determining what the final URL was after redirection.

BREAKING CHANGE: Technically a break, since `Response::new()` takes an
  additional argument. In practice, the only place that should have been
  creating Responses directly is inside the Client, so it shouldn't
  break anyone. If you were creating Responses manually, you'll need to
  pass a Url argument.

src/client/request.rs

@@ -110,7 +110,7 @@ impl Request<Streaming> {
     ///
     /// Consumes the Request.
     pub fn send(self) -> ::Result<Response> {
-        Response::with_message(self.message)
+        Response::with_message(self.url, self.message)
     }
 }
 

src/client/response.rs

@@ -1,12 +1,14 @@
 //! Client Responses
 use std::io::{self, Read};
 
+use url::Url;
+
 use header;
 use net::NetworkStream;
 use http::{self, RawStatus, ResponseHead, HttpMessage};
+use http::h1::Http11Message;
 use status;
 use version;
-use http::h1::Http11Message;
 
 /// A response for a client request to a remote server.
 #[derive(Debug)]
@@ -17,6 +19,8 @@ pub struct Response {
     pub headers: header::Headers,
     /// The HTTP version of this response from the server.
     pub version: version::HttpVersion,
+    /// The final URL of this response.
+    pub url: Url,
     status_raw: RawStatus,
     message: Box<HttpMessage>,
     is_drained: bool,
@@ -25,13 +29,13 @@ pub struct Response {
 impl Response {
 
     /// Creates a new response from a server.
-    pub fn new(stream: Box<NetworkStream + Send>) -> ::Result<Response> {
+    pub fn new(url: Url, stream: Box<NetworkStream + Send>) -> ::Result<Response> {
         trace!("Response::new");
-        Response::with_message(Box::new(Http11Message::with_stream(stream)))
+        Response::with_message(url, Box::new(Http11Message::with_stream(stream)))
     }
 
     /// Creates a new response received from the server on the given `HttpMessage`.
-    pub fn with_message(mut message: Box<HttpMessage>) -> ::Result<Response> {
+    pub fn with_message(url: Url, mut message: Box<HttpMessage>) -> ::Result<Response> {
         trace!("Response::with_message");
         let ResponseHead { headers, raw_status, version } = try!(message.get_incoming());
         let status = status::StatusCode::from_u16(raw_status.0);
@@ -42,6 +46,7 @@ impl Response {
             status: status,
             version: version,
             headers: headers,
+            url: url,
             message: message,
             status_raw: raw_status,
             is_drained: false,
@@ -89,6 +94,8 @@ impl Drop for Response {
 mod tests {
     use std::io::{self, Read};
 
+    use url::Url;
+
     use header::TransferEncoding;
     use header::Encoding;
     use http::HttpMessage;
@@ -131,7 +138,8 @@ mod tests {
             \r\n"
         );
 
-        let res = Response::new(Box::new(stream)).unwrap();
+        let url = Url::parse("http://hyper.rs").unwrap();
+        let res = Response::new(url, Box::new(stream)).unwrap();
 
         // The status line is correct?
         assert_eq!(res.status, status::StatusCode::Ok);
@@ -162,7 +170,8 @@ mod tests {
             \r\n"
         );
 
-        let res = Response::new(Box::new(stream)).unwrap();
+        let url = Url::parse("http://hyper.rs").unwrap();
+        let res = Response::new(url, Box::new(stream)).unwrap();
 
         assert!(read_to_string(res).is_err());
     }
@@ -181,7 +190,8 @@ mod tests {
             \r\n"
         );
 
-        let res = Response::new(Box::new(stream)).unwrap();
+        let url = Url::parse("http://hyper.rs").unwrap();
+        let res = Response::new(url, Box::new(stream)).unwrap();
 
         assert!(read_to_string(res).is_err());
     }
@@ -200,7 +210,8 @@ mod tests {
             \r\n"
         );
 
-        let res = Response::new(Box::new(stream)).unwrap();
+        let url = Url::parse("http://hyper.rs").unwrap();
+        let res = Response::new(url, Box::new(stream)).unwrap();
 
         assert_eq!(read_to_string(res).unwrap(), "1".to_owned());
     }